Bidirectional forwarding detection (BFD) is a set of international standard protocols for implementing fast detection, which provides detection with light load and short duration. The BFD detects link states in two directions by transmitting a detection packet at two ends of a bidirectional link simultaneously, so as to implement link failure detection in the level of milliseconds. A special case of a bidirectional link is a unidirectional link, for example, a label switched path (LSP). At this time, a BFD control packet needs to be transmitted in one direction only, and the peer end reports the link state through other paths.
The BFD allows failure detection on any types of channels between systems, where the channels include a direct physical link, a virtual circuit, a tunnel, a multi-protocol label switching (MPLS) LSP, a multi-hop route channel, and an indirect channel. Meanwhile, as the failure detection implemented by the BFD is simple and sole, the BFD is able to focus on fast detection of forwarding failures to help networks to transmit voice, video, and other on-demand services with a good quality of service (QoS), and help service providers offer, based on IP networks, Voice over Internet Protocol (VoIP) service with high reliability and high applicability and other real-time services required by their customers.
The BFD protocol describes two bidirectional detection mechanisms: an asynchronous mode and a query mode. In addition, an auxiliary echo function can be used in combination with these two modes. The essential difference between the asynchronous mode and the query mode is the detection position. In the asynchronous mode, the local end transmits a BFD control packet periodically, and the remote end needs to detect the BFD control packet transmitted by the local system, while in the query mode, the local system detects the BFD control packet transmitted by the local end.
Although the BFD detection can detect a connection state of a link, it cannot detect a quality problem of the link.
Multi-Protocol Label Switching transport profile (MPLS-TP) is a new MPLS protocol prototype based on Transport MPLS (T-MPLS) and Internet Engineering Task Force (IETF) MPLS. The requirements of an MPLS-TP network include contents in various aspects such as Operation, Administration, Maintenance (OAM), forwarding, control, management, and survivability, where the OAM is an important aspect of the transmission-oriented. MPLS-TP network. The MPLS-TP network has strict requirements for OAM tools: The OAM tools must measure performance parameters of the network such as packet loss, time delay, and jitter, and the QoS of the network is monitored by using the performance parameters. However, in the prior art, the network performance parameters are unable to be measured.